Scientology is called “a cult” so that average Joe does not get offended for his religious beliefs.
Did you? I didn’t know that “Do unto others…” was a religion.
What you did was the equivalent of seeing someone say that Harry Potter is a work of fiction and arguing that this is false because England is a real place.
Well, this gets difficult because you need to define which aspects of a religion you are talking about.
If you want to say you have to accept a given religion 100% then none come out very rational.
But then looking at the multitude of sects one can easily see there is disagreement aplenty about various details of a given religion.
If you carefully polled all the attendees of a given religious service I think you would find there is not 100% unanimity even within a congregation.
Still, within most religions we can find aspects I think most people would agree upon. For example thou shall not kill or thou shall not steal. Not sure you need a religion to tell you that but when one does I think we can all be ok with those parts.
Religion came about before there were codes of laws and police and courts to enforce the laws (or even after courts and laws existed but were dodgy in their application). Religion was a way to coerce adherence to a set of rules to allow a society to function.
As such I think we can point to some and say they were more (relatively speaking) rational in their goals than another religion. Certainly it is subjective and debatable which were better or more rational but I think it is abundantly clear Scientology is particularly off the rails in this regard.